There are different LED types for the led light bars,such as Epistar,CREE. CREE type leds are more popular than Epistar type leds. The led power is different from 15W to 300W. So you can choice it based on your requirements. Our waterproof garde is  IP67. The lifetime is 30000 hours. Normally,we just use aluminum material for the housing. Because the alluminum housing is easily to radiate the heat. We have different sizes of led light bars from 4inch to 50inch.